A recent study conducted by fertility specialists reveals that women giving birth after conceiving by fertility treatments in their 50s are able to cope with parenting as well as the younger mothers.

The results contradict the common view that older women may make less suitable mothers. Further, it follows the recommendations from the head of the British government's fertility watchdog, Lord Harries of Pentregarth, the former Bishop of Oxford, that 'women in their 50s and 60s should not be barred from having IVF on account of their age.'

In spite of there not being any official age limit for IVF in Britain, the National Health Service (NHS) doesn't support the treatment of women above the age of 40. Several private clinics are not willing to treat women above 45 years.

Most of the clinics refuse to treat older women even if they want to use eggs from younger mothers due to poor success rates and legislation according to which, doctors are responsible for the welfare of children born to IVF. The risk of stillbirth and ectopic pregnancy increases twice at the age over 45. The risk of pre-eclampsia and diabetes is approximately 3 times higher at the age above 55.

Patricia Rashbrook, 62, a child psychiatrist, became the oldest woman in Britain to have a baby. She had a boy child, 6lb 10oz (3kg), by caesarean section, after a fertility treatment in eastern Europe. She was condemned by several pressure groups.

Anne Steiner from the University of North Carolina, and Richard Paulson from the University of Southern California, carried out investigations determinining parental stress and the mental and physical health of women conceiving at the age over 50 after treatment with donor eggs, and compared them with women in their 30s and 40s who had conceived through IVF at the same time.

The findings of the survey conducted on 64 women revealed that there was no difference in the mental or physical health of those in their 50s from the women in their 40s and 30s. Parental stress was found to be the highest in women in their 40s and the lowest in those in their 30s. The women in their 50s showed parental stress of the level that was in-between the other 2 age groups.

Dr Steiner, who will present the findings today at the annual meeting of the American Society for Reproductive Medicine in New Orleans, said: "The conclusion ... is that if we look from the perspective of stress and physical and mental functioning, it doesn't seem we can restrict parenting based on these reasons. Many of the older women are married to significantly younger men, a factor that may help reduce the stress of motherhood, and they are financially comfortable. Their children are also no older than 12."

Gillian Lockwood, medical director at Midland Fertility Services, said: "The research supports decisions by some women to have children later in life. I don't agree with the view that men may father a child into their late 80s, but it's wrong for women to want to extend their fertility after 45. That's ageist and sexist."